Rear deck door lock for automobiles



March 25, 1941. c. F. KRAMER REAR DECK DOOR LOOK FOR AUTOMOBILES Filed Aug. 23, 1958 2 Sheets-Sheet 1 IN VENTOR. 6 5a rgnce ffKra/iier ATTO March 25, 1941. c. F. KRAMER REAR DECK DOOR LOCK FOR AUTOMOBILES Filed Aug. 25,1958 '2 Sheets-Sheet 2 INVENTOR.

-\TTORNEY$ Patented Mar. 25, 1941 UNITED STATES REAR DECK DOOR LOCK FUR AUTOMOBILES Clarence F. Kramer, Detroit, Mich, assignor to Ford Motor Company, Dearborn, Mich, a corporation of Delaware Application August 23, 1938, Serial No. 226,316

1 Claim.

This invention relates to improvements in the rear deck door locks of automobiles.

In the past, and also at the present time, the locks used in the automotive industry for the purpose of keeping the rumble seat door, or rear deck door, or baggage compartment door, as the case may be, securely shut, have not been entirely satisfactory. Their latching action is not sufficiently positive and hence troublesome situations arise, for example, where the door has to be slammed shut several times'before it will latch, or where the door will come unlatched while the car is in motion, or wherethe door will refuse to latch at all. These difficulties have resulted in a constant source of complaint to the automobile dealer and manufacturer.

It has been found that the source of the trouble lies in the fact that the automobile manufacturer, in respect to this feature, has been attempting to use a strictly conventional type of lock-the type in common use on the doors of all buildings--- in-an unconventional manner. The rear deck door differs from the ordinary door in'that there is a dissimilarity in its hinging and in the mannor in which it mates with the surrounding part or rear deck. This means that its arc of travel is different and that the position of latch bolt and striker at the instant of impact is correspondingly differentdue to this dilference in the arc of travel and the curvature of the rear portion of the automobile. The conventional lock in no way compensates for these peculiarities hence its unsatisfactory action naturally results.

The principal object of this invention is to produce a lock, particularly suited for use on the rear deck doors of automobiles, whose latching action is positive to the required degree for satisfactory operation.

One incidental object is to provide an improved lock that can be manufactured at no greater cost than the type of lock formerly employed.

Other objects and advantages will become more apparent from the following more detailed description and by reference to the drawings forming a part of this application and in which:

Fig. 1 shows a rear deck door of representative contour and cut away to show a lock of the old type in latched position;

Fig. 2 is an enlarged view in side elevation of the rear portion of the door of Fig. 1 showing the preferred form of the invention mounted in said door;

Fig. 3 is a view similar to Fig. 2 but on a larger scale and showing only the main assembly of the lock;

Fig. 4 is a side elevation of the structure shown in Fig. 3;

Fig. 5 is a section on the line 5--5 of Fig. 4;

Fig. 6 shows an alternate form of the invention assembled in a rear deck door, the lock being built as a smaller unit;

Fig. 7 is a plan view taken along the line 1-1 of Fig. 6, and

Fig. 8 is an end view of the lock shown in Fig. 7.

Referring to Figs. 2 to 5 of the drawings, the lock assembly II is mounted on the rear deck door l2 by any suitable means such as rivets l3 passing through the holes l4 provided for that purpose. Movement of the usual door handle I5 is transmitted to the bolt l6, drawing it away from the striker H, which is rigidly secured to the body of the car as indicated, thus permitting the door l2 to be opened. This movement of the bolt takes place by reason of the fact that the handle shaft I8 is fitted to the square hole ill in the handle cam 20 so that movement of the handle IE will cause a corresponding rotation of the handle cam whose faces contact bearing surfaces 2! on the bolt arm 22 causing it to be drawn back. The handle end of the bolt arm 22 and the handle cam 20 are held in position on the main plate 23 by means of the housing 24 which in turn is secured to said plate by lugs 25 preferably welded thereto. In order to confine the movement of the bolt arm 22 to a direction parallel to the longitudinal axis of the main plate 23, a guide clip 26 is secured to the main plate by lugs 21 and embraces the bolt arm 22 adjacent the bolt end thereof. The bolt arm 22 is formed with a hooklike end 28 which engages a pin 29 secured in, and extending between, the side walls of the latch bolt Hi. The latch which is formed as a U-shaped yoke member is pivoted in the housing 30, forming a part of the main plate 23, on the shaft 3| and radial movement of the latch bolt in a clockwise direction about this shaft is opposed by the action of the torsional bolt spring 32. Longitudinal mo tion of the bolt arm 22 is in turn opposed by the action of the handle cam spring 33 which is held in position on the main plate 23 by the clip 34 and one end of which bears against the lug 35 formed in the bolt arm. This arrangement of springs, as is customary in look. practice, insures that the latch bolt it will always return to the locked position after being displaced therefrom either by the action of the handle movement or by contact with the inclined cam surface 38 of the striker ll. As the hook-shaped end 28 of the bolt arm 22 engages but one side of the cross pin 29, the latch bolt I6 can move independently of the bolt arm 22 so that no rotation of the handle is required or necessary when the door is moved to closed position.

The alternate form of the invention shown in Figs. 6, '7 and 8 is precisely the same in principle, the only modification being that the bolt arm is omitted and motion of the handle 15' is transmitted to thelatch bolt directly by the action of the handle cam 20' bearing against the cam surface 31 provided on the latch bolt l6, and results in a unit having a smaller overall length, but a greater depth. In this form of the invention the movement of the handle necessary for unlocking is limited to one direction of rotation whereas in the preferred construction the handle can be moved in either direction of rotation and unlocking will result. In both illustrations of the invention, the door handle I 5 is equipped with a standard form of tumbler lock and key 4| for the protection of the car owner, according to established practice in the automotive industry.

The aforementioned difficulties encountered in conventional rear deck door lock installations have been accentuated by the recent trend in automotive design towards more streamlined contours resulting in more pronounced curvatures in the rear deck door, such as shown in Fig. 1, where the conventional type of latch bolt 32 is indicated in contact with the conventional type of striker 43. The line 44 shows the position of the locking surface of the latch bolt 12, and the line @5 indicates the are described by the door I2 in opening. For the conventional type of lock, the are described by the door [2 should form an angle of substantially with the face of the latch bolt 42, as indicated by the line 5;, in order to achieve the most positive and satisfactory locking conditions. But due to unavoidable space restrictions when a conventional type of lock is installed as indicated in the door !2 which has an actual path of movement along the line 45, the force against the locking surface of the latch bolt 42, tending to hold the door in closed position, would have a component in the direction of travel of said bolt. Hence the engagement between the latch bolt 32 and the striker 43 would not be sufficiently positive, and consequently if any considerable force were exerted to open the door, as for example by jimmying between .the meeting edges of the door and deck, the latch bolt could be readily moved back against its action spring entirely out of engagement with said striker, due to the action of said component of force in the direction of travel of said latch bolt. Since the improved lock described herein has an entirely different type of locking action, these difficulties are effectively overcome as is shown by the following discussion and explanation of the advantages of the invention.

It will be seen that the U-shaped latch bolt prevents the possibility of the rear deck door becoming unlatched by relative movement between said door and the body of the automobile resulting from any torsional action produced by road shocks, such movement becoming more notice able as the age of the car increases. In other words, when the door is locked its movement is not restricted merely in one direction by the action of the lock, as with the former constructions, but is confined in a horizontal direction as well as a vertical direction by the engagement of the bolt and striker.

But more important than this feature is that the latch bolt, being pivoted, moves into and out of locking position with a rotary rather than sliding motion, and that the mating faces of bolt and striker 3B and 39, which produce the locking action, are carefully designed with curved instead of flat surfaces in order to compensate for the curvature of the rear deck and the arc of travel of the deck door.

Thus, by locating the pivoted axis All of the bolt l6 above and forwardly of the locking face 39 of the striker I I, and by reason of the curvature of the mating faces of bolt and striker, the locking action is made more positive and effective.

Upon analyzing the source of this locking action it can be readily seen that it is produced by the locking face of the striker engaging the mating surface 38 of the latch bolt. This means that the force tending to hold the door closed is transposed to the lock assembly and thence to the door itself by the latch bolt !6 mounted on its pivoted axis 40; or in other words, since the rearward and downward force tending to hold the door closed can be assumed to extend approximately radially from said pivotal axis, said force can be considered as primarily concentrated at said pivoted axis and then transmitted through the lock assembly to the door. Therefore this type of lock has a great advantage in that it is capable of being modified to give positive locking action in any installation by merely locating the pivotal axis of the latch bolt in the most suitable position, depending upon the characteristics of each particular design.

The correct location of the pivotal axis of the latch bolt and the proper degree of curvature to use on the mating surfaces of bolt and striker may readily be determined from the curvature of the rear deck and the arc the deck door describes when opened which of course depends upon the design of hinge used.

Another feature of this type of lock is worthy of note and that is that its design is such that all the principal parts in the lock assembly are fabricated of sheet steel stampings which keeps the manufacturing cost down to a minimum.

It will be understood that many changes and modifications may be made of the structures herein selected for illustration and falling within the scope of the following appended claim:

I claim:

A latch structure for a, pivoted door having a door frame and a door panel and hinges connecting the upper end of said panel to said frame with said panel being arcuate in section taken normal to the axis of said hinges and the outer surface of said panel being convex, comprising, a substantially flat main plate secured to the inside of said panel adjacent the free edge thereof and disposed in a position which substantially approaches that of a tangent to the arc of said panel at the free end thereof, said main plate being positioned between said panel and a chord connecting the hinged and free ends of said panel, a bolt arm mounted on said main plate for longitudinal motion With respect thereto, a latch operating means engaging said bolt arm and extending outwardly therefrom through an opening in said panel, a latch bolt having a curved latching surface pivotally mounted on said main plate adjacent the free end of said panel, said pivot being so positioned that when said latch bolt is in locked position, said curved latching surface is substantially tangent to said chord, said latching surface being adapted to engage a striker secured on said frame having a coacting surface complementary to said latching surface and so disposed that the contact between said latching and said coacting surfaces is substantially along said chord, for the purpose described.

CLARENCE F. KRAMER. 

